The present invention relates generally to vehicle spring suspensions and more particularly is adapted to a leaf spring suspension device suitable for attachment to vehicle rear suspension springs.
It is the usual practice to isolate the rear axle of a vehicle from the frame of the vehicle by supporting the axle in a multi-leaf type spring which is suspended between a forward bearing bracket and a rearward spring shackle whereby most imperfections in the road surface can be absorbed by the wheel and the spring construction and not be transmitted to the vehicle passenger compartment through the frame. The multi-leaf type of spring is characterized by a plurality of stacked leafs, usually four or five in number, which decrease in length away from the base or mounting leaf in the form of a truncated triangular configuration. The axle suspension connects to the thickest or highest part of the multi-leaf spring to achieve maximum support.
Occasionally, when a vehicle is utilized to carry especially heavy loads, the existing leaf springs have a tendency to sag or flex sufficiently to wrap-up or permit "bottoming." Also, upon unusual wear or unusual surface conditions, the existing springs could allow "forward pitch" or "nose dive" of the vehicle, all to the discomfort of the passengers.
In order to enhance the load bearing capabilities of light pickups, trucks, or the like, prior art stabilizing devices have been proposed. Such prior art devices are either made up of a large number of parts, do not adapt easily to preexisting structure or are not totally effective in compensating for heavy loads on the vehicle's suspension system.
FIG. 4 is a prior art illustration of a multi-leaf spring 10b similar to leaf spring 10 of FIG. 1. Like numerals refer to like parts of FIG. 1. Here, instead of brackets 17 and 18 as in FIG. 3, spaced brackets 170 (only 1 visible in FIG. 4) encircle pre-existing axle 171 having spaced legs 172, 173 terminating in threaded ends 174, 175, respectively, receivable in spaced holes 176, 177, respectively, in bracket plate 178. Conventional threaded nuts 179 and washers 180 are used to secure brackets 170 to plate 178.
As indicated by arrow 181, the direction of torque taking place on axle 171 is illustrated. This torque, as indicated by arrows 182, 183 (assuming spring 10b is mounted to the vehicle as in FIG. 3), causes wrap-up of the spring 10b which provides sag or flex sufficient to bottoming out of spring 10b.
There is a need for a leaf spring suspension device that is quickly and easily adaptable to the preexisting leaf spring of a vehicle, such as light body pick up truck, and that is effective and has relatively low number of parts.